1. Field of the Invention
The present invention relates to a belt-type continuously variable transmission having a resin block belt, and a motorcycle including this belt-type continuously variable transmission.
2. Description of Related Art
JP-A-2002-147582, for example, discloses a motorcycle which includes a belt-type continuously variable transmission having a resin block belt. The resin block belt has a higher durability than that of a conventional rubber belt, and a belt-type continuously variable transmission that uses the resin block belt therefore has a higher durability as well.
A resin block belt is formed by combining a plurality of resin blocks having a higher hardness than that of rubber. Thus, the sound generated by collisions between a resin block belt and a primary or a secondary sheave is larger than the sound generated by collisions between a rubber belt and the primary or secondary sheave. Thus, noise generated from a belt-type continuously variable transmission using a resin block belt is greater than noise generated from a belt-type continuously variable transmission using a rubber belt.
In order to reduce the noise generated by the resin block belt, JP-A-2002-147582 considers a structure that includes a sound absorbing material disposed inside and outside a transmission case. However, even when sound absorbing material is provided inside and outside the transmission case, it is difficult to sufficiently prevent escape of noise generated by the resin block belt to the outside.